1. Field of the Invention
The present invention relates in general to wireless communications and, more particularly, to a portable communication device employing one or more interfaces that can selectively receive power or different power-on states depending on which interface receives a communication signal over a wireless medium, or which interface is user-selected or programmed to receive the signal while other interfaces can be selectively powered down to conserve battery life.
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
In recent years, there has been a significant market increase in portable electronic devices, such as laptop computers, notebooks, palm-size computers, and personal digital assistants (PDAs). Unlike desktop computers and the like, portable or mobile computing devices generally operate off batteries that must be periodically recharged. Presently available batteries have limited storage capabilities, and it is important that portable computing devices limit their power draw when various subsystems are not being used. There is known a wide range of techniques for conserving power in portable, battery-powered computing devices. Typically, power conservation includes shutting down subsystems (or portions) of the computing device by placing the device in various states of operation such as, for example, suspend, sleep, and standby states.
As portable devices have become more popular, the central processing and memory management functions can be achieved through lower power integrated circuits. Moreover, a greater emphasis has been placed on the communication capability of the portable device since many devices rely less on processing speed and more on being able to communicate over a wireless medium. Therefore, the proliferation of cellular and wireless technology had led to a dramatic increase in what is known as “wireless” computing devices. Wireless devices are generally used to communicate with one another without cable or wires therebetween. Wireless communication has led to an increase in the mobility of the portable device since it allows transmission and communications from virtually any location where a wireless or cellular system is present.
With the increased emphasis on communication features, the continuum of different power consumption states (i.e., suspend, sleep and standby), used in conventional portable devices proves ineffective when such devices employ wireless communication. A significant purpose behind a wireless portable device is to be able to receive messages from an external source at all times. If the portable device is in a sleep, suspend, or standby state, it is possible that the receiver within the interface of the portable device is powered down and therefore incapable of receiving the incoming signal. In order to alleviate this problem, typical portable devices generally maintain power to the communication interface circuits at all times in order to receive and recognize incoming messages regardless of when such messages are sent.
The interface circuit generally includes an amplifier, a clock recovery circuit, and possibly an oscillator associated with that recovery circuit, all of which consume considerable amounts of power. The problem is compounded whenever the portable device has multiple interface circuits or radios onboard. For example, many portable devices might have a Bluetooth® interface, a GSM/GPRS interface, a wireless local area network interface, a code division multiple access (CDMA) interface, as well as possibly other RF interfaces associated with a single portable device. If all such interfaces remain powered on, the battery life is substantially lessened, thus making the portable device impractical for many applications.